MATERIAL - This analog display wall clock made of acrylic material with white letters and numbers, ideal for classrooms or the office. Special Design - The black clock face was designed to look like a blackboard, with each math equation painted to look like white chalk. Instead of traditional numbers, this wall clock has a different equation for each delimitation. Funny Mathematical - The pointer moves around the watch face to indicate the time of day through a different math problem for each hour. A unique and creative way to keep track of time, this wall clock is a fun and challenging brain exercise. If you can read this watch, you are undoubtedly a math geek. Each lesson is marked by a simple math problem. Solve it and solve the riddle of time. Ideal for the budding math student or for anyone who wants something different in a watch. Application - Great for the budding math student or anyone who wants something different in a watch. For classroom, study, living room, nanny bedroom, office. Product Note: Regarding the battery, the battery is not included, please use the carbon-zinc battery, please do not use the rechargeable battery or other batteries, due to the high output current of these batteries, the accuracy of the clock may be affected.Specifications: Material: Acrylic Color black Shape: Round Size: 30 x 30 / 11.8 x 11.8 inches Power: 1 AA battery (not included) Unique appearance and good performance, look fashionable and show accurate time. The watch measures 11.8 inches in diameter, it is easy to see from a distance. A unique and creative way to keep track of time, this wall clock is a fun and challenging brain exercise. Each lesson marked by a simple math equation can overwhelm your fear simply by solving some simple math problems with each corresponding lesson. Great gift idea. Give one of these wall clocks to a math teacher, engineer, mathematician, or anyone who loves straight numbers. A very fashionable decoration for the wall, especially for the classroom, office and study, as well as an ideal gift for your friends or their children. Package Includes: 1 * Math wall clock